Hi,
HikaShop store the address details in the user session because if the user does not continue in the checkout, the address will be refill automatically with the rest of his cart.
It is possible to empty this session, the best will be to empty it at the end of the checkout.
So the best is to override the checkout end view or to create a custom plugin which will trigger the "onAfterOrderCreate" function.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.